    var cwjkeyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
   
    function encode64(input) {
       input = escape(input);
       var output = "";
       var chr1, chr2, chr3 = "";
       var enc1, enc2, enc3, enc4 = "";
       var i = 0;
   
       do {
          chr1 = input.charCodeAt(i++);
          chr2 = input.charCodeAt(i++);
          chr3 = input.charCodeAt(i++);
   
          enc1 = chr1 >> 2;
          enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
          enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
          enc4 = chr3 & 63;
   
          if (isNaN(chr2)) {
             enc3 = enc4 = 64;
          } else if (isNaN(chr3)) {
             enc4 = 64;
          }
   
          output = output +
             cwjkeyStr.charAt(enc1) +
             cwjkeyStr.charAt(enc2) +
             cwjkeyStr.charAt(enc3) +
             cwjkeyStr.charAt(enc4);
          chr1 = chr2 = chr3 = "";
          enc1 = enc2 = enc3 = enc4 = "";
       } while (i < input.length);
   
       return output;
    }

function decode64(input) {
      var output = "";
      var chr1, chr2, chr3 = "";
      var enc1, enc2, enc3, enc4 = "";
      var i = 0;
  
      // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
      var base64test = /[^A-Za-z0-9\+\/\=]/g;
      if (base64test.exec(input)) {
         alert("There were invalid base64 characters in the input text.\n" +
               "Valid base64 characters are A-Z, a-z, 0-9, '+', '/',and '='\n" +
               "Expect errors in decoding.");
      }
      input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
  
      do {
         enc1 = cwjkeyStr.indexOf(input.charAt(i++));
         enc2 = cwjkeyStr.indexOf(input.charAt(i++));
         enc3 = cwjkeyStr.indexOf(input.charAt(i++));
         enc4 = cwjkeyStr.indexOf(input.charAt(i++));
  
         chr1 = (enc1 << 2) | (enc2 >> 4);
         chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
         chr3 = ((enc3 & 3) << 6) | enc4;
  
         output = output + String.fromCharCode(chr1);
  
         if (enc3 != 64) {
            output = output + String.fromCharCode(chr2);
         }
         if (enc4 != 64) {
            output = output + String.fromCharCode(chr3);
         }
  
         chr1 = chr2 = chr3 = "";
         enc1 = enc2 = enc3 = enc4 = "";
  
      } while (i < input.length);
  
      return unescape(output);
   }